What is bc number means.

Forums Pellets, Projectiles, Slugs, & Ammo What is bc number means.

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    Ok I'm looking at .25 slug and its bc is .100. Vs the bc of .22 cal is .078. Does bigger number mean better bc or lower number means better bc? Which have the better bc between. 25 cal and .22 cal?



    bigger number is better



    Bigger is better, and the correlation is linear.  I.e., a BC of .05 is twice as susceptible to the wind effects as a BC or .1.  Size does matter in this case…  ;)

    • This reply was modified 1 year ago by Centercut.


    BC is a can of worms and dependent on the G drag functions applied, and the A-B distance(s) used to calculate; BC is a dynamic value. My guess is most are applying G1.

    It's also helpful to know the rifle that was used to calculate the value, since two rifles shooting the same projectile will sometimes produce different BCs



    HI BC stands for ballistic coefficient , and this means how well it flys threw the air , So the higher BC number the better if flys , like an airplane .

    Years ago they figured out they needed a model to base different  flights of bullets ,So you will see words like G1 OR G7  , WELL  G1  was the first model to base ammo from , the G1 was one inch in diameter and weighed 1 pound , so things were compared to this

    Today we make more aerodynamic bullets so we needed a upgraded system  so g7 came in to be the current drag model it is more of a sleek long pointed bullet , so , when you see numbers like with pellets from  say .0018 to .0046  the higher number flys better so it will drop less and buck wind less ,

    Slugs for airguns have much better BC I am a small bore slug shooter and they have Ballistic coefficients from say .0690 to .240 ,that I use ,

    So these fly much better so they fly longer distances and drop less and they retain energy a very long way , when you are a pinker or short range hunter bc really dont matter if you know where your pellet lands at say 25 to 35 yards .

    However when you shot long range with real guns then your BC is an input for caculating your shots , as to make a proper ballistic table you need to put in all kinds of information to make the shot ,

    here is examples


    1 .    you shooting a pellet gun sighted in at 50 yards , you see a squirrel at  38 yards , just aim a whisker low and yu got him


    2.you have a lapua .338 and you see a zombie coming at you  and he is 2700 yards . and you sighted in at 100yd

    you cant just aim like Kentucky wind-age in movies , so

    1. you check inputs like temperature of air , you ranged zombie 2700 yds

    2 you input you barometric pressure

    3 alltitude

    4spin drift


    6 ammo temp on real guns as powder higher temp makes more fps

    7.direction of zombie

    8. angle of shot

    9. corolis


    9 you will need you basic ballistic dope sheet to input everything  so you know basic  poi ,

    10. you dial or hold and then you take shot on wind call last holding

    11.lead if target is moving

    so with all data you get your final dope for shot , their is alot of math and such small miscalculation can miss by many feet at long ranges , and also , when shooting say point blank with pcp or gun you can be off with distances and still make a good hit when you reach out ,the angle of the slug is on such an angle that you can miss by mis ranging target from 2700 to , and you input say 2780 , you just shot over the target 6 feet ,

    and say same senaro target is at 180 yards and you range 100 , , and you shot , you would of killed zombie as bullet at this point is not at a huge angle descending to earth .

    so I am trying to say  this is what it means and how it works and what you would use it for

    hope it helps






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